1. Field of the Invention
The present invention relates to a pump, and more particularly to a telescopic dual movement pump that is able to pump air outward in movements in two opposite directions. Further, the tubes of the pump are telescopic so that the size is compact for storage.
2. Description of Related Art
Pumps are used to pump air into an object to be inflated and very common in different fields. A most commonly seen pump has a handle securely connected to a piston that is received in a tube. When the user moves the handle rearward relative to the tube, air is sucked into the tube. When the user pushes the handle, the piston forces the air sucked into and received in the tube out of the tube so as to accomplish the purpose of pumping air to the object. However, because the travel distance of the piston is short and the user can only force the air outward by pushing the piston forward, operation of the pump is very exhausting and labor inefficient.
In order to overcome the shortcoming of short travel distance of the piston, another pump is introduced to the market and has several tubes sequentially received in the other tubes so that the pump tubes are telescopic. When the tubes are extended and the handle is pushed, the piston inside the rearmost tube is driven to move to the frontmost tube so as to force the air out of the pump. Because the travel distance of the piston is increased, the quantity of air being forced out of the pump is accordingly increased when compared with a conventional one.
Either one of the pumps requires the user to move the handle backward to suck air into the pump so that the user is able to force the air out of the pump. That is, only when the piston is moving toward the frontmost tube, the air is forced to escape from the pump. Therefore, neither of the pumps enables the user to pump air outward from the pump no matter which direction the piston is moving so as to save energy for the user.
To overcome the shortcomings, the present invention tends to provide an improved telescopic dual movement pump to mitigate and obviate the aforementioned problems.
The primary objective of the present invention is to provide an improved telescopic dual movement pump, wherein the pump has a central tube, a first tube enclosing the central tube and movable relative to the central tube and a second tube enclosing the first tube and movable relative to the first tube so that the pump is telescopic.
Another object of the present invention is that a first piston assembly is provided to a distal end of the central tube and a second piston assembly is provided to a distal end of the first tube so that the movement of the first piston assembly as well as the second piston assembly is able to force air out of the pump from the central tube.
Still another objective of the present invention is to provide two deformable air pads so that no matter the second piston assembly is moving toward or away from the central tube, one of the air pads will have air tight engagement with an inner periphery of the second tube so as to force air into the central tube.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.